Self-sealing test plug



Jan. 8, 1952 s. s. JOHNS sELF-sEALING TEST PLUG Filed Oct. 7, 1946 Patented Jan. 8, 1952 SELF-SEALING TEST PLUG Stanley S. Johns, Baltimore, Md., assigner to Rheem Manufacturing Company, Richmond, Calif., a corporation of California Application October 7, 1946, Serial No. 701,807

13 Claims. l

The application relates to test plugs for pressure vessels and has particular reference to a self-sealing test plug which is adapted to utilize the pressure Within the vessel to assist in making a tight seal between 'the plug and theY vessel.

Among the objects oi the invention is to provide a quick and positive acting means for closing the openings in vessels which are to be tested by internal pressure under conditions where heretofore considerable difliculty has been encountered in providing a leak-proof seal Which could be quickly applied and removedand still be of such construction as to be capable of Withstanding high test `pressures built up in the vessel.

Another object Vis to provide a new andimproved self-sealing test plug for boilers, tanks and similar vesselswhich .is inexpensive to manufacture and which is capable of `being installed and released with a minimum of effort.

Still another object of the invention is to provide a new and improved self-sealing test plug in which `the Working parts have been` kept to substantially a minimum providing thereby a rugged,` positive-acting plug'.

`With these and other objects in View, the invention consists in the construction, arrangement and combination of the various parts of the device. whereby the objects contemplated are attained, as hereinafter more fully set forth,

pointed out in the claims and illustrated in the accompanying drawings, in which:

`Figure l is a longitudinal, sectional view of the self-sealing test plug` showing the parts in locked position ready for insertion into a boiler, J

tank or other pressure vessel.

p Figure 2 is a longitudinal, sectional view similar to that of Figure 1 showing the parts in sealed position with the plug inserted Within an aperture in the vessel.

Figure 3 is a cross-sectional View takenon the line 3--3 oi Figure l.

Figure 4 is a` bottom View.

Figure 5 is a fragmentary, elevational view showing the test plugin the process of being insertedinto a tank aperture.

Figure 6, is` a fragmentary, longitudinal, sectional View showing an auxiliary connection to the device.

In vesselscsuoh as boilers, tanks, drums and vessels of similar types which are designed to withstand a considerable amount of pressure seine means becomes advisable to satisfactorily testthe strengthioi the vessel after it has been assembled. When the vessel is provided with apertures of one type or' another to permit access to the interior, it is necessary to eliecti'vely'seal the apertures while the vessel is being tested. Obviously, the more rapidly the sealing means can be inserted and released the more rapidly the test can be completed. For this reason test plugs which are required to be bolted orY other- Wise attached to the aperture by the use of Wrenches or other auxiliary tools are not in great favor because of the time and inconvenience necessary to apply and remove them.

In an embodiment of the invention illustrating a self-sealing test` plug, Which is adapted to automatically seal itself in an aperture upon being inserted therein, there is shown a device comprising a cylindrical housing bottom Il and open `at the end opposite the bottom. Within the cylinder is a piston l2 designedto reciprocate with respect to the interior Wall of the cylinder. Extending centerably through the piston is a bore I3 within which is positioned a pull rod I4, the pull rod being adapted to i'lt loosely within the bore so as to provide an annular passage in the bore around the pull rod.

At the upper'end of the 'bore is an enlarged portion i5 inwhich is housed a coiled spring l5, the coiled spring being adapted to press against ashoulder l1 Within the piston at the junction of the enlargement with the bore I3 and pressing at the other end against the bottom Il.

Athreaded portion 20 of the pull rodY extends threadably throughthebottom Il and is locked in placeby a lock nut 2l. A sealing Washer 22 between the lock nut and the adjacent face of the bottomV makes certain thatno vleak of pressure may occur through the aperture in the bottom through Whichthe pull rod passes.

Atv the outside end of the piston is an annular recess 23 within which is positioned a sealing gasket or seat member 2li, the seat member being held out of contact with the pull rod by a sleevelike extension 25 of the piston. The pull rod is provided with a head 2B having fiat faces 21 to facilitate insertion into an aperture in a tank.

As best shown in Figures 2 and 5, the test plug is adapted to be applied to a tank, boiler or similar type of vessel, illustrated in part by a wall 39 having one or more apertures 3i therein around which is applied a conventional Spud or fitting 32. rI he apertures are ordinarily those to which permanent connections to the vessel will eventually be made. Threads are eventually provided on the spud'for the connections, but as I0 having a 3 a general rule the tests are made prior to threading.

As best understood from an examination of Figure 5, the flat faces 2'I on the head 26 of the pull rod I4 permit the insertion of the head through a hole or aperture 33 in the spud 32 but provide also for a lip or protrusion sufficient to firmly grasp the spud at the inside of the aperture.

Between the bottom I I of the cylinder and the piston I2 there is formed a chamber 35, sealed except for the space between the pull rod and the bore I3 which provides communication between the chamber and the exterior of the test plug. To provide the piston with a snug sealing t, at its inside end a cup washer 36 is attached to the piston by utilization of screws 31. The screws aided by a washer 38 hold the cup washer in proper position. The cup washer and the washer 38 are provided with axially aligned holes through which pass the pull rod and the coiled spring I6.

To further improve the operability of the test plug there is incorporated into its construction means making it possible to hold the piston I 2 in retracted position within the cylinder I0. This means comprises a latch 39 pivotally mounted upon a bracket 40 at the side of the cylinder by a pivot pin 4I. A spring 42 normally tends to rotate the latch in a clockwise direction, as viewed in Figures 1, 2 and 3. The latch is designed to engage a flange 43 at the outside end of the piston, the latch being provided with a hooked end 44 for this purpose.

In operation when it is desired to seal the aperture 33, the self-sealing test plug is adjusted initially so that the piston I2 is in the retracted position shown in Figure 1. In this position the coiled spring I5 will be contracted, and the piston will be pressed far enough into the cylinder so that the latch engages the flange 43 where it is retained in latched position by pressure of the spring 42.

As thus adjusted, the pull rod I4 projects a substantial distance beyond the member 24. The same relationship of parts is illustrated in Figure 5- wherein the pull rod is shown in the act 0f being inserted into the aperture 33. After the head of the pull rod is located beneath the conventional spud 32, the latch is released by thumb pressure upon an end 45. Once released, the -coiled spring I6 presses the piston outwardly with relation to the head of the pull rod, and the parts assume the relationship illustrated in Figure 2.

Up to this point it is only the pressure of the spring IG which is relied upon to press the member or gasket 24 into sealed relationship with the rim of the aperture 33 in the conventional spud 32. The head of the pull rod serves only -as an anchoring member. Although the pressure of the spring I need not be of any great force, it is sufficient to provide an initial sealing effect.

With the test plug thus positioned, liquid or vessel which is being tested the greater will be the pressure against the inside end of the piston I2. The effect of the pressure upon the piston .is augmented by utilization of the familiar hydraulic principle in that the interior end of the piston presents a relatively vlarge area responsive to the thrust of pressure as compared with the annular area of the seat member surroundingY the bore I3 and within the line of the seal. By this device a greater force is developed Within the chamber of the test plug than is developed around the circumference of the opening to be sealed; that is to say, the line of contact between the sealing member 24 and the edge of the spud 32. It is significant that the diameter of the chamber 35 is substantially greater thanY the diameter of the line of sealing contact between the sealing member 24 and the spud 32.

By reason of this relationship, no matter how great the pressure may be in the vessel, the pressure on the piston rendering the seal effective will always be greater. Many types of tanks are adapted to employment of the test plug described herein wherein test pressures vary over a con'- siderable range. Frequent employment of the test plug is made in testing tanks where liquid test pressures reach 350 pounds per square inch and gas test pressures reach 30 pounds per square inch.

To remove the sealing plug after pressure is released within the vessel the cylinder is pushed against the piston far enough so that the latch again engages the ange 43. Once engaged, the pull rod is eiectively maintained in an extended position relative to thev piston, and the head of the pull rod can be worked out of the aperture 33 by merely tilting it slightly and withdrawing at an angle. Withdrawal is thus accomplished efliciently and with considerable ease. In the last described position the test plug is ready im# mediately for insertion into an aperture of another vessel to be tested.

On occasions where the tank to be tested may have but one aperture some means need frequently be provided for applying pressure to the interior. In a modified form of the test plug the cylindrical housing I3 may be provided with a threaded aperture 5I communicating with the chamber 35 in which a fitting 52 may be inserted and attached to a fluid line53. Either liquid or gasfor testing may be initially passed into the vessel through the fluid pressure line 53 into the chamber 35 and from the chamber through the bore I3 into the vessel.

In order to render my plug universal for use in connection with containers whether the aperture in which it is used is on a flat or a cylindrical surface, I prefer to form the gasket 24 frustroconical, that is, having a tapered surface such as is illustrated in Figures` 1 and 2. It is, of course, apparent that the inner diameter is smaller than the diameter of the aperture and the outer diameter is larger so that upon insertion into the aperture, a contact is formed between the gasket 24 and the peripheral edge of the aperture.

It will also be noted that the sleeve 25 extends beyond the lower outer edge of the cylinder I2 so that it will .extend partially into or through the aperture. The purpose of extending the sleeve inwardly is to provide a substantially solid backing for `the gasket 24 to prevent its being pushed or deformed inwardly against the stem I4 upon the application of pressure.

It will also be noted that the upper face of the head 26 is formed with a tapered surface. Such construction is desirable to aid in centering the plug in the aperture.

Althoughftheinvention,h-as-beenrherensshown -and'fdescribed nfwhat, is `conceiveditobe the most practical and' .preferred embodiment, it lisvrecog.-

nizedlthatfdeparturesaman be made therefrom within the scope of the. inventionywhich not toubef limited to` the details; disclosed hereinbut isnto. be accorded. the fullscope. of'the `claims so.. as 11o-'embrace anysand all equivalent structures..

.The invention `having been. herein described, whaty is claimed: and vsought to .be secured by Letters :Patent is.: E

.1. A self-.sealing test` plug' comprising: a heus.- ing member-having a closed end,1a reciprocating member in the housingmember forming therewith-an inner chamber, a transversely disposed Vseal-ing element. on-onezmember adapted-to engage in sealing contact with a `rimoi anaperture ina vessellto be tested, ananchoring means Acomprising stem secured tothe `other of said members and anchor head secured to said stem a'd-aptedote be extended into the aperture for `engagement with thednnersurfacaof said vessel, and a `passage communicating between the y'chamber and the interior (5f-said vessel.

`2. A-"selff-sealing test plug vcomprisinga housy ingmember having'a closed end, a reciprocating member inthe `housing member forming therewith-an inner chamber, -a transversely disposed sealing element on one'member adapted to engageiin sealing-*contact-Witha rim of an aperture in la vessel to be tested, ananchoring means comprising a stem secured at oneend-thereof `to said `other member and an anchor lhead secured to the other end'ithereof adapted to be` extended into the apertureiorengagement `.with lthe` inner ysurface of said vessel, and a passage communicating'between the chamber and the interior of said vessel, the area o'f-said chamber transverse of the linefof reciprocationof said reciprocating Vmember being greaterY than the area of said aperture.

-3-. 'A self-sealingtest plug lcomprisinga housing-memberhaving-'afclosed end, a reciprocating member inthe `housing member forming therewith an inner chamber, a transversely disposed sealing element-'secured to.v one membe-riadapted toengage in sealing Contact with a :of an aperture in av `vessel to be tested,` an anchoring means secured to the other member adapted tovbe extended into. :the `aperture for engagement with the inner side` of the vesseLapassage communicating `between the chamber and the interior of` said vessel, the area of saidchamber transverse of theline of reciprocation of said l,

the interior of ,the cylinder, the fluid exposed.

area on saidpiston facing said chamber `transverse of the lineofmovement betweensaid piston and cylinder being-.greater than the `fluid exposed areaiacing; said aperturetransverse of said line,L whereby pressure introduced into the chamber-trom, Asaid vessel is. adapted `toossist in 'forcing said piston, outwardly vrelative lto` the cylinder, andimeans vforfreleasably holding said piston inwardly relatiyelyxtozthecylinder-,during application :of: the plugV to the `aperture in tsad vessel.

'5. .Ascii-sealing, test plug for pressure vessels having van aperture; in, thefwallthereof comprising "a cylinder and' a. vpiston. slidable, therein torming an. interior chamber, means for sealing said piston lagainst the rim Vof `said aperture, anchoring means onsaid cylinderadapted to, be anchored in said aperturara'passage communicatingthrough the, aperture between `said vessel and the, interiorxof the cylinder, the, fluidexposed area on, said piston facing said chamber trans- `verseof thefline oi' movement betweensaid pis,-V ton and cylinder :being greater-than the fluid exposed'area, facing'said aperture transverse, of said "line, whereby pressure introduced into the chamber from said vessel is adapted'to assistin forcing4 said .pistonoutwardly-` relative to the; cylindergsaid passage comprising a bore: through the. pistonv adjacenty the axis. thereof having, one end terminating in the chamber and the. other end terminating, atfthevoutside end of the piston., and means for releasably `holding said pis-ton` inwardlyrrelatiye to the cylinder during application of thepl-ug to the aperture in said'vessel.

6. A self--sealingjtest plug for pressure `vessels having ai test `aperture therein comprising .a housing having .enclosed `end,a piston 'slidably mounted thereinandlforming achamber in the housing, a pull rod extending througlrll said piston and attached to `the-closed end of the housing and a pull head on the other end adapted .to extend through` said aperture and engage. at one side thereof, passagemeans through-said piston adapted tocommunicate `with the chamber, and sealing means on the piston around the passage means adapted to 'seal against the edge oithe aperture en the'side Aopposite .saidppull head.

7. A self-sealing tesi-,plug for a tted aperture in pressure vessels comprising a housing having aclosedend and an open end, a pistonslidable into the open end and forming a chamber in the housing, saidpiston `having, a central bore, apull rod `extending through said bore having one end attached tothe closed end ofthe cylinder anda pull head on `the other end adapted to project through said. aperture and engage at one side thereof, passage `means through said bore .round the pull rod adapted to communicate with-the chamber,` spring meansadapted tofmove the. vpiston 'outwardly toward the pull head, and sealing means on the piston `around the bore adapted to.- sea-l against` the edge of the aperture Qnthe side opposite said pull head.

8,-.` A self-sealingtest plug for a tted aperture in pressure `vessels i comprising c a cylinder having a closed-end and an, open end., apiston slid-able into `the open end and forming a chamber' in the cylinder, said piston `having a. central bore, l-a pull rod extending through said bore` having one end `attached to theclosed .end rof `the cylinder and a Bullhead on the other end adapted-to extendthrough said aperture andengage atene side thereof, passage.V means through said bore around the pui-1f rod adapted to communicate with the chamber, Spring. means adapted, to; move thepiston outwardly toward the pull; head, sealing,.mean.s onl the piston aroundthe bore adapted to A sealagainst the edge Jof Lthe aperture on the sideopposite saidpull head, and a latch, having parts, respectively on `the cylinder` and-piston: re.- 4 leasabl-v holdingasaid piston vin wrntdly-w relative to the cylinder and the pull head when interlocked.

9. A self-sealing test plug for a fitted aperture in pressure vessels comprising a cylinder having a closed end and an open end, a piston slidably mounted in the cylinder and extending through the open end forming a chamber within the cylinder, said piston having a central bore communicating with said chamber and with the exterior, a pull rod extending through said bore having one end extending threadably through the closed end of the cylinder and a pull head on the other end adapted to extend through said tted aperture and engage one side thereof, passage means through said bore around'the pull rod adapted to communicate at one end with said aperture and at the other end with the chamber, a recess at the inside end of the piston, a compression spring in the recess compressed between the piston and the closed end of the cylinder, sealing means on the piston around the bore adapted to seal against the edge of the aperture on the side opposite said pull head, and a latch having parts respectively on the cylinder and piston releasably holding said piston inwardly relative to the cylinder and the pull head in extended position when interlocked.

10. A self-sealing test plug comprising a housing member having a bottom, a reciprocating member in the housing member forming an inner chamber adjacent said bottom, a transversely disposed sealing element secured to one member adapted to engage in sealing contact With the rim of an aperture in a vessel to be tested, an anchoring means secured to the other member adapted to be extended into the aperture for engagernent therein, a passage communicating between the chamber and the aperture at a location within an area of contact of the sealing element and the rim, and an aperture through the housing Wall adapted to receive a pressure line fitting for passing test fluid under pressure through the test plug into the vessel.

11. A means for sealing an aperture in therwall of a container While fluid pressure is introduced into the interior of said container comprising an annular resilient gasket adapted to be Vcompressed against the outer surface of said container adjacent the periphery of said aperture, means for holding said gasket in compression againstI said container comprising ananchor head having a minor diameter less than the diameter of said aperture and a major diameter greater'than said aperture and formed with an upwardly tapered upper surface adapted to contact the inner surface of said container adjacent said vaperture and to center said resilient gasket with respect to said aperture, means for urging said head and said gasket together responsive to said fluid pressure, said means comprising a piston and cylinder assembly defining an expansible pressure chamber, one of the members of said assembly being formed with a circumferential groove adapted to receive said annular gasket, said head member being movable in association with the other of said members of said assembly, resilient means adapted to urge said piston and cylinder apart thereby urging lthe gasket and anchor head together to effect an initialseal between said gasket and said aperture, the fluid exposed area on the assembly member receiving vsaid gasketand facing-said chamber transverse of the line of movementbetween the members of said assembly being greater than the uid exposed area facing said aperture transverse of said line, and a passageway adapted to communicate pressure between the interior o said container and said expansible chamber to urge said piston and cylinder assembly members apart and to eifect a greater seal between said gasket and said aperture.

l2. A means for sealing an aperture in the wall of a container while fluid pressure is introduced into the interior of said container comprising an annular resilient gasket adapted to be compressed against the outer surface of said container adjacent the 'periphery of said aperture, means for holding said gasket in compression against said container comprising an anchor head having a minor diameter lessY than the diameter of said aperture and a major diameter greater than said aperture and being adapted to contact the inner surface of said container adjacent said aperture, means for urging said head and said gasket together responsive to said fiuid pressure, said means comprising a cylindrical housing and a piston slidably disposed therein and defining an expansible pressure chamber, said piston being formed with a circumferential groove adapted to receive said annular gasket and having a concentric sleeve member extending through said annular gasket, the fluid exposed areapn said piston facing said chamber transverse of the line of sliding between housing and piston being greater than' the fluid exposed area facing said aperture transverse of said line, said anchor head being movable with said cylindrical housing, resilient means adapted to effect an initial seal between said gasket and said aperture, means `for releasably holding said housing and piston together in opposition to said resilient means and a passageway adapted to communicate pressure between the interior of said container and said expansible chamber to urge said housing and piston apart and to effect a greater seal between said gasket and said aperture.

13. A means for sealing an aperture in the wall of a container while iiuid pressure is introduced into the interior of said container comprising an annular resilient gasket having a tapered sealing face adapted to be compressed against the outer surface of said container adjacent the periphery of said aperture, means for holding said gasket in compression against said container comprising an anchor head having an upwardly tapered upper surface adapted to contact the inner surface of said container adjacent said aperture and to center said resilient gasket with respect to said aperture, means for urging said head and said 'gasket together responsive to said fluid pressure, said means comprising a cylindrical housing having one closed end and a piston slidably disposed in the other end and defining an expansible pressure chamber, said piston being formed with a circumferential groove adapted to receive said annular gasket and having a concentric sleeve member extending through said annular gasket, the fluid exposed area on said piston facing said chamber transverse of the line of sliding between housing and piston being greater than the fluid exposed area facing said aperture transverse of said line, said head member being movable with said cylindrical housing, resilient means adapted to urge said housing and piston apart to effect an initial` seal between said gasket and said aperture, said means comprising a compression spring disposed between said piston and the closed end of said cylindrical housing, means for releasably holding said housing and piston together in opposition to said resilient means, and a passageway adapted to communicate pressure between the interior of said container and said expansible chamber to urge said housing and piston apart and to effect a seal between said gasket and said aperture resistant to testing pressures.

STANLEY S. JOHNS.

REFERENCES CITED The following references are of record in the le of this patent:

Number 10 UNITED STATES PATENTS Name Date Swangren Oct. 6, 1908 Carlson Mar. 7, 1916 Domenico Mar. 11, 1919 Kothe Aug. `28, 1923 Klinner May 20, 1924 OBrien Feb. 22, 1944 

